STRUCTURE OF CEREAL-LEGUME HERBALS WITH DIFFERENT METHODS OF SOWING AND IRRIGATION IN ARID CONDITIONS OF THE LOWER VOLGA

In recent years, livestock farms in the Astrakhan region have mainly used grasses from natural hayfields and pastures for fodder. But, due to the sharp aridization of the climate, and, as a consequence, the more frequent droughts, as well as the unregulated growth of the number of animals on farms, the reserves of natural herbage are often insufficient. Therefore, the region began to increase the area of sown hayfields for irrigation. The aim of the work is to study the effect of various irrigation methods on the productivity of cereal-leguminous mixtures with multi-cut use in the conditions of light chestnut soils of the Northern Caspian region. The studies were carried out in 2017-2020 in the Astrakhan region. All studied irrigation methods (sprinkler irrigation, drip irrigation with a belt laying depth of 0.0, 0.15, 0.25, 0.35 and 0.45 m, periodic flooding), with the exception of subsoil irrigation, with an ordinary method of sowing contributed to the development of both cereals and legumes. In these variants of the experiment, cereals occupied a significant part in the total herbage - from 40.0 to 61.0%. When using the spread sowing method, only in one variant, the share of cereal grasses was 54.0% (periodic flooding). In all others with this method of sowing, the amount of cereals in the total mass was insignificant, or they were completely absent. The widespread method of sowing was also the most productive in all the years of research. The maximum yield in the experiment was noted in all variants of the experiment in the third year of the life of grasses in 2019.The highest productivity with the spread method of sowing was noted in 2019 in the variants of the experiment with a belt laying depth of 0.25, 0.35 and 0.45 m and amounted to 98.1, 104.4 and 111.0 t/ha, respectively. In the variants with the row-sowing method, the yield was lower than with the wide-spread one. The highest yield with this method of sowing was also noted in 2019 in variants with subsurface drip irrigation with a belt laying depth of 0.35 and 0.45 m and amounted to 105.5 and 104.8 t/ha, respectively

Aspects of formation of soil water regime and water consumption of corn under subsurface drip irrigation

The results of experimental researches on studying of features of formation of a water mode of soils, water consumption processes, and corn yield under different schemes of irrigation pipelines (IP) under subsurface drip irrigation (SDI) in the Steppe of Ukraine. The wetting zone of dark-chestnut residual-saline sandy soil (SI "SF "Brylivske") changed. There is a shift of the center relative to the drip water outlet into deeper horizons of the soil profile (up to 52 cm) with the increasing norm; soil layer 0-15 cm is almost not moistened, regardless of watering rate. At a distance of IP 1,0 m closing of wetting zones, occur at irrigation rates of 2,7 m3/100 running meter (r. m), and at a distance of IP 1,4 m does not occur even at irrigation rates of 3,7 m3/100 r. m, while the depth of wetting reaches 90 cm. The wetting zone of chernozem sandy loam on the loess species (SI "SF "Velyki Klyny") with irrigation rates of 2,7 m3/100 r. m was observed on the soil surface. The maximum depth of wetting, with irrigation norms of 3,7 m3/100 r. m, reached 70 cm with a maximum diameter of 79 cm at a depth of 25 cm. Closing of wetting zones was not observed. Studies at SI "SF "Brylivske" have confirmed that the depth of IP placement (on the soil surface or at a depth of 30 cm) influenced the formation of the soil water regime and the corn yield. The minimum total water consumption was 6271 m3/ha under drip irrigation (DI) (IP 1,4 m), 17 % more than SDI (IP 1,4 m), and 29% more than SDI (IP 1,0 m). The highest yield was obtained in the case of DI (IP 1,4 m) of 15,72 t/ha. SDI (IP 1,0 m) received 13,93 t/ha, and SDI (IP 1,4 m) received 13,50 t/ha. The distance between the IP in 1,0 m and 1.4 m of the SDI system did not significantly affect corn yield (13.93 and 13.50 t/ha, respectively), but at a distance of IP 1.4 m, the water consumption ratio was 6.8% less compared to IP 1,0 m. The value of the irrigation rate in the variants SDI (IP 1.0 m) was higher than SDI (IP 1,4 m) by 13,6 %. Therefore, in terms of irrigation water consumption and capital expenditures, the SDI (IP 1,4 m) is more economical. Experimental studies conducted in the SI "SF "Velyki Klyny" show that the depth of placement of IP (on the soil surface or at a depth of 20 cm) did not affect the corn yield. For DI (IP 1,0 m) the yield was 12,00 t/ha and for SDI (IP 1.0 m) was 12,10 t/ha, with a water consumption ratio of 533,8 m3/t, and for DI (IP 1,0 m) by 3,6 % more. The research results confirm the importance of the parameters of SDI system for the formation of soil water regime and, accordingly, the realization of the potential of varieties and hybrids of crops for their cultivation by SDI.

IRRIGAÇÃO POR GOTEJAMENTO SUBSUPERFICIAL EM CULTIVARES DE CANA-DE-AÇÚCAR IMPACTAM A AGREGAÇÃO DO SOLO?

IRRIGAÇÃO POR GOTEJAMENTO SUBSUPERFICIAL EM CULTIVARES DE CANA-DE-AÇÚCAR IMPACTAM A AGREGAÇÃO DO SOLO? YASMIN REIS MAGALHÃES1; ANDERSON PRATES COELHO2; CAROLINA FERNANDES1; ALEXANDRE BARCELLOS DALRI2 1 Departamento de Ciências da Produção Agrícola, Universidade Estadual Paulista (Unesp), Faculdade de Ciências Agrárias e Veterinárias, Via de Acesso Professor Paulo Donato Castellane, s/n Km 5, 14884-900, Jaboticabal, São Paulo, Brasil. [email protected]; [email protected] 2 Departamento de Engenharia e Ciências Exatas, Universidade Estadual Paulista (Unesp), Faculdade de Ciências Agrárias e Veterinárias, Via de Acesso Professor Paulo Donato Castellane, s/n Km 5, 14884-900, Jaboticabal, São Paulo, Brasil. [email protected]; [email protected] 1 RESUMO Objetivou-se avaliar o efeito da irrigação por gotejamento subsuperficial em cultivares de cana-de-açúcar, contrastantes na responsividade à irrigação, na agregação de Latossolo argiloso. O experimento foi realizado em Latossolo Vermelho eutroférrico, de textura argilosa (587 g kg-1 de argila). Foram coletadas amostras deformadas de solo em vinte pontos em cada uma das quatro áreas de cana-de-açúcar avaliadas nas camadas 0,00-0,10 m e 0,10-0,20 m. As áreas correspondiam ao cultivo irrigado e não irrigado, das cultivares CTC 4 e IACSP93-3046. Foram determinados e calculados o índice de estabilidade dos agregados, diâmetro médio ponderado de agregados, fracionamento físico do carbono orgânico e as classes de agregados. Os dados foram submetidos à estatística descritiva e multivariada de fatores. De acordo com as correlações das variáveis, a agregação do solo foi dividida em dois processos, sendo o primeiro denominado de “Dimensão de agregados” e o segundo “Estabilidade de agregados”. Observou-se que a irrigação por gotejamento subsuperficial promove maior “Estabilidade de agregados” do solo em áreas cultivadas com cana-de-açúcar. Além disso, cultivares de cana-de-açúcar proporcionam diferenças na agregação do solo, sendo que a cultivar responsiva à irrigação IACSP93-3046 promove maior “Dimensão de agregados” do solo em relação a cultivar não responsiva CTC 4. Palavras-chave: diâmetro médio ponderado de agregados, estabilidade de agregados, carbono orgânico, Latossolo. MAGALHÃES, Y. R.; COELHO, A. P.; FERNANDES, C.; DALRI, A. B. DOES SUBSURFACE DRIP IRRIGATION IN SUGARCANE CULTIVARS IMPACT SOIL AGGREGATION? 2 ABSTRACT The aim was to evaluate the effect of subsurface drip irrigation with sugarcane cultivars, contrasting in the responsiveness to irrigation, in the aggregation of Oxisol clayey. The experiment was conducted in a clayey Oxisol (587g kg-1 of clay). Deformed soil samples were collected at twenty points in each four areas of sugarcane evaluated in the layers 0.00-0.10 m and 0.10-0.20 m. The areas corresponded to the irrigated and non-irrigated cultivation of cultivars CTC 4 and IACSP93-3046. The aggregate stability index, weighted average diameter of aggregates, physical fractionation of organic carbon and aggregate classes were determined and calculated. The data were submitted to the descriptive and multivariate factor statistics. According to the correlations of the variables, soil aggregation was divided into two processes, the first being called “Aggregates dimension” and the second “Aggregates stability.” It was observed that subsurface drip irrigation promotes greater soil “Aggregate stability” in areas cultivated with sugarcane. Additionally, sugarcane cultivars provide differences in soil aggregation, and the cultivar responsive to irrigation IACSP93-3046 promotes a larger soil “Aggregates dimension” than the non-responsive cultivar CTC 4. Keywords: weighted average diameter of aggregates, aggregate stability, organic carbon, Oxisol.

Assessment of fodder corn grown under surface and subsurface drip irrigation in Mendoza, Argentina

Drip irrigation –surface (DI) and subsurface (SDI)– is one of the best irrigation systems to increase both irrigation and water use efficiency. The objective of this research is to assess and compare the response of fodder corn to SDI treatments at two depths with DI in Mendoza. A full factorial experimental design was used on random plots and measurements were replicated through time. Tests were run in two consecutive cycles. Germination percentage (GP), yield, water use efficiency (WUE) and water productivity (WP) were assessed. High yields ranging from 70,214 to 105,771 kg ha-1 of green matter and from 10,020 to 22,476 kg ha-1 of dry matter (DM) were obtained in both cycles, respectively. DM production from the first sowing was significantly higher in both cycles under SDI treatment than under DI. No significant differences in WP or WUE were found. GP and soil moisture (SM) did not show differences between treatments, but significant differences were found in SM (p=<0.0001) between the first soil layer and the other two layers. Highlights Germination percentage was not affected by the depth of the drip irrigation lines. No significant differences were found in green matter yields between treatments in both crop cycles. High crop water use was achieved. WUE values were 12 percent (and up to 41 percent) higher.

Comparison of aerobic rice cultivation using drip systems with conventional flooding

In this study, yield and water productivity response of rice to various irrigation levels applied with subsurface and surface drip systems in 2019 and 2020 in the Mediterranean Region of Turkey was evaluated in comparison with conventional flooding (CF). The treatments consisted of two irrigation methods namely surface drip (DI) and subsurface drip systems (SDI), three irrigation levels designated as plant pan coefficients (I1.00: Evaporation from Class A pan (Ep) × 1.00; I1.25: Ep × 1.25 and I1.50: Ep × 1.50) and CF as control. The effects of drip systems and coefficients on yield and yield components were statistically significant (P < 0.01). DI produced higher yield than SDI. CF produced significantly greater yield than both DI and SDI systems. With two drip systems, average water savings of 60.5% in I1.00, 54.5% in I1.25 and 49% in I1.50 were achieved as compared to CF. However, yield reductions of 15% in I1.50, 20% in I1.25, 29% in I1.00 were observed for DI; corresponding values for SDI were 20, 28 and 44%, respectively. Drip irrigation in aerobic rice production system had almost twice the water productivity based on total irrigation water applied (WPI) or total water input (irrigation + rainfall) (WPI+P) compared with CF. During the study years, the highest WPI and WPI+P values were found in DI-I1.00 (0.81–0.73 kg/m3) and (0.85 and 0.74 kg/m3), respectively. In conclusion, DI-I1.50 treatment is recommended for sustainable aerobic rice production since DI-I1.50 resulted in water saving of 49% but yield decrease of 15% as compared to CF.